Libra Colour in invert (not dark) mode flashes to white every page turn

[RobertJSawyer]

I'm visually impaired and need a black background everywhere — and so I use "Invert Mode" (as distinct from the standard "Dark Mode" available through the stock user interface). "Invert Mode" is available through NickelMenu and inverts everything (book, dictionary, user menus, home screen — everything):

menu_item :main :Invert & Reboot :nickel_setting :toggle :invert

On my old Libra 2, that worked just fine: everything (the book, dictionary, and all other UI elements) had a black background, which only switched to white during a page refresh (which I had set to every chapter).

But I've just bought a Libra Colour, and in "Invert Mode," regardless of what setting I have for "refresh pages," the background flashes to white for each page change.

NOTE: If I use standard "Dark Mode," instead of "Invert Mode," this does NOT happen -- but then the dictionary and UI elements all have white backgrounds, making the Libra Colour useless for me.

Any suggestions, other than returning the Libra Colour?

[PeterT]

I wonder if it might be related to the issue mentioned near the end of the NickelClock thread?

[RobertJSawyer]

Hi, Peter. I tried installing NickelClock 0.4.0 (the latest), which is supposed to fix a specific screen-flashing problem on the Libra Colour after highlighting a passage, but it makes no difference to my overall problem of the screen going white after every page turn.

It's really disappointing, as otherwise the Libra Colour is a lovely device.

[PeterT]

No. I don't think NickelClock would solve the issue; it's just that the author mentions an issue in the Kobo firmware that caused a most annoying flicker with NickelClock and I was wondering if that underlying issue is the one causing the darkmode problems

[RobertJSawyer]

A few observations I've made during additional testing:

The flashing to white every page turn happens regardless of which renderer you're using: it happens for both .kepub and plain sideloaded .epub files.

BUT it is not a necessity brought about by the colour layer. If you press and hold on the lower right corner of the screen when a book is open, the Libra Colour does high-speed paging forward with NO bounce to a white screen between pages (and if you press and hold the lower left, no bounce occurs as it pages backward).

NOR is this required when updating screens with colour on them. For instance, there's no bounce to white when paging through "My Books" (or any other multipage menu).

[RobertJSawyer]

(And, of course, this is NOT a NickelMenu issue; if you have DevModeOn, you can toggle "Invert screen" there — Nickel Menu is just a handy way to do that more quickly.)

[Aleron Ives]

I don't know if this would help, but you could try editing Kobo eReader.conf on your computer and changing numPartialUpdatePageTurns to a high number like 50, then save the file, eject your Libra, and reboot it. This might be enough to force the screen refreshes to go away, but it's possible this is just a bug with inverted mode, since you're not supposed to be using it.

[RobertJSawyer]

Originally Posted by Aleron Ives

I don't know if this would help, but you could try editing Kobo eReader.conf on your computer and changing numPartialUpdatePageTurns to a high number like 50, then save the file, eject your Libra, and reboot it. This might be enough to force the screen refreshes to go away, but it's possible this is just a bug with inverted mode, since you're not supposed to be using it.

Before I modified it, the value for numPartialUpdatePageTurns was already set to 4294967295, which is obviously a lot higher than 50. Still, I tried what you suggested, and it didn't help. But thank you!